Climate change: A simmering threat to our ocean

Frank Bainimarama knows all about the need to protect the ocean. As the prime minister of Fiji, he runs a country made up of more than 300 islands in the South Pacific. This week, he’s been co-hosting the first ever UN conference on the ocean in New York, along with Sweden’s Climate Minister Isabella Lovin, focusing on sustainable development and conservation of the world’s oceans, seas and marine resources.

Speaking to the assembled leaders from government, science, business and civil society, Bainimarama – also the incoming president of this year’s UN Climate Conference in November – made it clear that ocean protection and climate change are inextricably linked.

“Climate change poses the biggest threat the world has ever known,” he said. “And the quality of our oceans and seas is also deteriorating at an alarming rate. They are interlinked, because rising sea levels, as well as ocean acidity and warmer waters, have a direct effect on our reefs and fish stocks and the prosperity of our coastal communities.” (…)

An acid bath?

Alongside the extra heat, the CO2 we have indirectly been dumping into the ocean has another devastating impact.

“The extra carbon dioxide, when it gets dissolved into the ocean, through various simple chemical equations, will increase the PH or acidification in the ocean,” Avery explained. Seawater is already at least 26 percent more acidic than it was before the onset of the Industrial Revolution in the 19th century, according to the “State of the Ocean” report published by the International Programme on the State of the Ocean back in 2013. The report found the ocean could be 170 percent more acidic by the end of the century.

Over the last 20 years, scientists around the world have been conducting laboratory experiments to find out what that would mean for the flora and fauna of the ocean. Ulf Riebesell, a professor of biological oceanography at Geomar, conducted the world’s first experiments in nature off the coast of the Norwegian archipelago of Svalbard in 2010.

The on-site experiments showed that increasing acidification decreases the amount of calcium carbonate in seawater, making life very difficult for sea creatures that use it to form their skeletons or shells. This change will affect coral, mussels, snails, sea urchins and starfish, as well as fish and other organisms, Riebesell told DW.

“Some of these species will simply not be able to compete with others in the ocean of the future,” he said.

That could have severe economic and social consequences, as acidification ultimately affects the food chain. Riebesell pointed out that coral reefs, for instance, are home to numerous species, serve as nurseries for fish, attract tourists and protect coastlines against waves and storms.

Riebesell has headed the German projectBIOACID (Biological Impacts of Ocean Acidification) for the last eight years. It’s expected to publish a summary of its results ahead of the UN climate conference in Bonn in November.

Hot problem for cold water

Polar areas are most affected by ocean acidification, as cold water is able to more quickly absorb CO2. Experiments in the Arctic, which is already warming around twice as fast as the global average, indicate that the seawater there could become corrosive within a few decades, Riebesell said. “That means the shells and skeletons of some sea creatures would simply dissolve.”

At a working meeting of the BIOACID group in Kiel last week, IPCC co-chair Hans Pörtner told DW that ocean acidification, a relatively young research field, had already made its way into the policy arena.

“It’s being considered as one of the climate challenges for the ocean, and it’s also considered in the context of sustainable food supply, especially for developing countries,” he said.

But even countries like the United States are already feeling the effect, said Pörtner. On the country’s west coast, ocean acidification is already threatening oyster cultures, and he said this economic impact has increased awareness of the problem.

Scientists are also concerned that the increasing amount of CO2 being stored in the ocean could, in turn, create a feedback effect that could further exacerbate global warming.

In the long run, the ocean will become the biggest sink for human-produced CO2, but it will absorb it at a slower rate.

“Its buffer capacity will decrease, the more acidic the ocean becomes,” said Riebesell.

Science and policy

Pörtner told DW that the writing is on the wall. “We really have to go into ambitious mitigation, if we want to have a chance to keep this under control.”

Carol Turley, senior scientist at the Plymouth Marine Laboratory in the UK, is highlighting the issue of ocean acidification at the UN conference in New York this week. She told DW that a combination of local management measures and global action were necessary to protect the ocean and implement the UN’s sustainable development goals.

“Although acidification, warming, sea level rise and oxygen loss represent global challenges requiring international agreements, there are varied options for reducing other stressors while efforts continue to reduce emissions of carbon dioxide to the atmosphere,” she said.

Turley said it was “inspiring” that UN Secretary-General Antonio Guterres and the co-chairs of the ocean conference, Fiji and Sweden, had recognized the key role of climate-related ocean stressors, including ocean acidification, and that the combined impact of these may threaten the implementation of the UN’s Sustainable Development Goal 14 (SDG 14), which focuses on the ocean and life below water.

She said it was also heartening to hear their messages of hope. “It’s not too late to fix the ocean. This shows how the evidence from science has been taken up by policy makers,” she said.

‘Stay optimistic’

Martina Stiasny, a young climate scientist from the Geomar Helmholtz Centre for Ocean Research in Kiel, Germany, told conference participants in New York about her research on how climate change-induced ocean acidification is affecting fisheries.

“We are already starting to see the first effects in the oceans,” she told DW. “It’s imperative that we start to act now. Otherwise it poses a serious threat to the health of the marine ecosystems and food security. It’s not only important for the SDG 14, but also links to most other SDGs in terms of human health, fighting hunger and poverty and most other goals.”

The landmark ocean conference has been taking place against the background of US President Donald Trump’s decision to take the US out of the 2015 Paris climate agreement, a move Stiasny describes as a “major disappointment.”

But she takes heart from the widespread movement to press ahead with emissions reductions and a transition to renewable energy.

“The statement that America made by pulling out is of course the wrong message to send to the world,” she said. “But fighting climate change is done every day by everyone on this planet and I believe we have no choice but to stay optimistic.”